Fix errors under 5.x and allow selecting warps from a dropdown (#5)

- Loading would previously fail if there was both no data in mod_storage "warps" and no warps.txt
- A wrong variable used while adding the warp queue was causing crashes when attempting to warp
- Don't even attempt to teleport to a warp spot that doesn't exit
- Allow selecting warps from a dropdown for ease of use, but still allow text input as warps might be created later than the warp crystals are created (negotiable, invalid input could be dropped and only the combobox allowed if others object).

.luacheckrc

@@ -0,0 +1,16 @@
+read_globals = {
+	"DIR_DELIM",
+	"core",
+	"dump",
+	"vector", "nodeupdate",
+	"VoxelManip", "VoxelArea",
+	"PseudoRandom", "ItemStack",
+	"AreaStore",
+	"default",
+	table = { fields = { "copy", "getn" } }
+}
+
+globals = {
+	"minetest"
+}
+

init.lua

@@ -10,9 +10,9 @@ of the license, or (at your option) any later version.
 
 --]]
 
-warps = {}
-warps_queue = {}
-queue_state = 0
+local warps = {}
+local warps_queue = {}
+local queue_state = 0
 local warps_freeze = 5
 -- t = time in usec
 -- p = player obj
@@ -22,14 +22,19 @@ local S = minetest.get_mod_storage()
 assert(S, "mod_storage is required")
 
 -- import warps or load
-local store = S:get("warps")
-local worldpath = minetest.get_worldpath()
-if store then
-	warps = minetest.deserialize(store)
-else
+local function firstload()
+	local store = S:get("warps")
+	local worldpath = minetest.get_worldpath()
+	if store then
+		warps = minetest.deserialize(store)
+		return
+	end
 	local fh,err = io.open(worldpath .. "/warps.txt", "r")
 	if err then
-		minetest.log("action", "[warps] loaded ")
+		-- If it doesn't exist, we've never used this mod before.
+		if not err:find("No such file or directory") then
+			minetest.log("error", "[warps] Error trying to load warps.txt: " .. err)
+		end
 		return
 	end
 	while true do
@@ -90,7 +95,7 @@ local warp = function(player, dest)
 	minetest.sound_play("warps_plop", {pos = pos})
 end
 
-do_warp_queue = function()
+local function do_warp_queue()
 	if table.getn(warps_queue) == 0 then
 		queue_state = 0
 		return
@@ -140,7 +145,7 @@ local warp_queue_add = function(player, dest)
 	end
 	-- force mapblock send to player, if supported
 	if player.send_mapblock then
-		player:send_mapblock(vector.divide(dest, 16))
+		player:send_mapblock(vector.divide(pos, 16))
 	end
 end
 
@@ -236,6 +241,32 @@ minetest.register_chatcommand("warp", {
 	end
 })
 
+local function prepare_dropdown(x,y,w,h,curr_dest)
+	local dd = string.format("dropdown[%f,%f;%f,%f;ddwarp;", x, y, w, h)
+	local sel = 0
+	for idx, warp in ipairs(warps) do
+		local warpname = warp.name
+		dd = dd .. minetest.formspec_escape(warpname) .. ","
+		if curr_dest == warpname then
+			sel = idx
+		end
+	end
+	dd = dd .. ";"..tostring(sel).."]"
+	return dd
+end
+
+local function prepare_formspec(dest)
+	local custdest = ""
+	if not lookup_warp(dest) then
+		custdest = dest
+	end
+	return "size[4.5,3]label[0.7,0;Warp destination]"
+		.."field[1,2.2;3,0.2;destination;Future destination;"
+		..minetest.formspec_escape(custdest).."]"
+		.."button_exit[0.7,2.7;3,0.5;proceed;Proceed]"
+		..prepare_dropdown(0.7,0.4,3,1, dest)
+end
+
 minetest.register_node("warps:warpstone", {
 	visual = "mesh",
 	mesh = "warps_warpstone.obj",
@@ -254,8 +285,7 @@ minetest.register_node("warps:warpstone", {
 	},
 	on_construct = function(pos)
 		local meta = minetest.get_meta(pos)
-		meta:set_string("formspec",
-			"field[destination;Warp Destination;]")
+		meta:set_string("formspec", prepare_formspec(""))
 		meta:set_string("infotext", "Uninitialized Warp Stone")
 	end,
 	on_receive_fields = function(pos, formname, fields, sender)
@@ -263,15 +293,24 @@ minetest.register_node("warps:warpstone", {
 			minetest.chat_send_player(sender:get_player_name(), "You do not have permission to modify warp stones")
 			return false
 		end
-		if not fields.destination then
+		if not (fields.destination and fields.quit) then
 			return
 		end
+
+		local dest
+		if fields.destination == "" and fields.ddwarp then
+			dest = fields.ddwarp
+		else
+			dest = fields.destination
+		end
+
 		local meta = minetest.get_meta(pos)
-		meta:set_string("formspec",
-			"field[destination;Warp Destination;" .. fields.destination .. "]")
-		meta:set_string("infotext", "Warp stone to " .. fields.destination)
-		meta:set_string("warps_destination", fields.destination)
-		minetest.log("action", sender:get_player_name() .. " changed warp stone to \"" .. fields.destination .. "\"")
+
+		meta:set_string("formspec", prepare_formspec(dest))
+		meta:set_string("infotext", "Warp stone to " .. dest)
+		meta:set_string("warps_destination", dest)
+		minetest.log("action", sender:get_player_name() .. " changed warp stone at "
+			.. minetest.pos_to_string(pos) .. " to \"" .. dest .. "\"")
 	end,
 	on_punch = function(pos, node, puncher, pointed_thingo)
 		if puncher:get_player_control().sneak and
@@ -283,12 +322,16 @@ minetest.register_node("warps:warpstone", {
 
 		local meta = minetest.get_meta(pos)
 		local destination = meta:get_string("warps_destination")
-		if destination == "" then
+		if destination == "" or lookup_warp(destination) == nil then
 			minetest.chat_send_player(puncher:get_player_name(),
 					"Unknown warp location for this warp stone, cannot warp!")
 			return false
 		end
+		minetest.log("action", string.format("Going to warp player %s to waypoint %s",
+			puncher:get_player_name(), destination
+		))
 		warp_queue_add(puncher, destination)
 	end,
 })
 
+firstload()